We present preliminary results of an Earth observation approach for the study of past human occupation and landscape reconstruction in the Central Sahara. This region includes a variety of geomorphological features such as palaeo-oases, dried river beds, alluvial fans and upland plateaux whose geomorphological characteristics, in combination with climate changes, have influenced patterns of human dispersal and sociocultural activities during the late Holocene. In this paper, we discuss the use of medium- and high-resolution remotely sensed data for the mapping of anthropogenic features and paleo- and contemporary hydrology and vegetation. In the absence of field inspection in this inaccessible region, we use different remote sensing methods to first identify and classify archaeological features, and then explore the geomorphological factors that might have influenced their spatial distribution.

Human expansions motivated by the spread of farming are one of the most important processes that shaped cultural geographies during the Holocene. The best known example of this phenomenon is the Neolithic expansion in Europe, but parallels in other parts of the globe have recently come into focus. Here, we examine the expansion of four archaeological cultures of widespread distribution in lowland South America, most of which originated in or around the Amazon basin and spread during the late Holocene with the practice of tropical forest agriculture. We analyze spatial gradients in radiocarbon dates of each culture through space-time regressions, allowing us to establish the most likely geographical origin, time and speed of expansion. To further assess the feasibility of demic diffusion as the process behind the archaeological expansions in question, we employ agent-based simulations with demographic parameters derived from the ethnography of tropical forest farmers. We find that, while some expansions can be realistically modeled as demographic processes, others are not easily explainable in the same manner, which is possibly due to different processes driving their dispersal (e.g. cultural diffusion) or problematic/incomplete archaeological data.

The interpretative power of quantitative intra-site spatial analysis has long been recognised by archaeologists. On the contrary, very few ethnoarchaeological works have engaged with the statistical analysis of intra-site pattern of artefacts and ecofacts. Nonetheless, ethnoarchaeology is uniquely placed to guide and assist in the identification of sound techniques and in the development of the methodology of analysis. The possibility to directly connect the distribution of the proxies under study with the activity that generated such distribution, provide the means of fine-tuning the tools we use for identifying these patterns in the archaeological record. As a consequence, archaeological methodology and interpretation both benefit from the application of improved methodologies. In this paper we review some of the most common techniques used to analyse activity areas and we provide examples of the application of such techniques to ethnoarchaeological contexts. The aim is to assess how archaeology can benefit from the intra-site spatial analysis of ethnoarchaeological contexts.

In this paper, we present a pilot study aimed at investigating the impact of subsistence strategies and environmental pressure on the distribution of ethnographically documented strategies to cope with drought and its effects across 35 current societies in Africa. We use freely accessible ethnographic databases to retrieve data on how a number of African societies deal with the circumstances of drought, and ascertain the impact of geography on their distribution in order to measure possible relationships between them, a set of subsistence choices, and proxies of environmental constraints. We use Canonical Correspondence Analysis to explore the emerging patterns and find that subsistence strategy strongly impacts the choice of drought management strategies, especially if considered with a proxy of local environmental condition. Spatial proximity and aridity per se have only marginal impact, highlighting other relevant processes of cultural transmission that at least partly transcend (a) the intensity of human interaction over geographic gradients and (b) local adaptation primarily dependent on water availability. This study supports the wide applicability of quantitative and replicable methods to cross-cultural evidence on a variety of adaptive strategies and uses ethnographic data to propose new hypotheses that can inform future archaeological research by showing recurrent and non-case-specific choices highlighting resilient practices and adaptive behaviour in Africa.

The domestication of plants and the origin of agricultural societies has been the focus of much theoretical discussion on why, how, when, and where these happened. The ‘when’ and ‘where’ have been substantially addressed by different branches of archaeology, thanks to advances in methodology and the broadening of the geographical and chronological scope of evidence. However, the ‘why’ and ‘how’ have lagged behind, holding on to relatively old models with limited explanatory power. Armed with the evidence now available, we can return to theory by revisiting the mechanisms allegedly involved, disentangling their connection to the diversity of trajectories, and identifying the weight and role of the parameters involved. We present the Human-Plant Coevolution (HPC) model, which represents the dynamics of coevolution between a human and a plant population. The model consists of an ecological positive feedback system (mutualism), which can be reinforced by positive evolutionary feedback (coevolution). The model formulation is the result of wiring together relatively simple simulation models of population ecology and evolution, through a computational implementation in R. The HPC model captures a variety of potential scenarios, though which conditions are linked to the degree and timing of population change and the intensity of selective pressures. Our results confirm that the possible trajectories leading to neolithisation are diverse and involve multiple factors. However, simulations also show how some of those factors are entangled, what are their effects on human and plant populations under different conditions, and what might be the main causes fostering agriculture and domestication.

Biagetti, S., J. Alcaina-Mateos, and E. R. Crema. 2016. A matter of ephemerality: the study of Kel Tadrart Tuareg (southwest Libya) campsites via quantitative spatial analysis. Ecology and Society 21(1):42.http://dx.doi.org/10.5751/ES-08202-210142